leupeptins and Carcinoma--Ovarian-Epithelial

Ovarian cancer is a disease with the highest mortality in gynecologic malignancies. Activation of STAT3 pathway is well known to be associated with tumor progression and metastasis in a number of cancers, including ovarian cancer. Therefore, STAT3 may be an ideal target for ovarian cancer treatment.. The present study aims to determine the antitumor activity of STAT3 inhibitor Napabucasin as a single agent or in combination with proteasome inhibitor MG-132 in ovarian cancer cells.. MTT was performed to determine the anti-proliferative effect of Napabucasin on ovarian cancer SKOV-3 cells. The involved anti-tumor mechanism was explored by flow cytometry, qRTPCR and western blot. MDC staining and tandem mRFP-GFP-LC3 fluorescence microscopy were used to analyze the autophagy-inducing capability of Napabucasin with or without MG-132. The combinational anticancer effect of Napabucasin and MG-132 was evaluated according to Chou and Talalay's method (1984).. Napabucasin showed obvious tumor-inhibitory effects against SKOV-3 cells. Treatment by Napabucasin arrested cell cycle progression in G2/M phase. Mechanistically, elevated expression of p21 may contribute to the blockade of the cell cycle. Moreover, we demonstrated that Napabucasin induced autophagy in SKOV-3 cells by using various assays, including MDC staining, autophagic flux examination, and detection of the autophagy markers. In addition, a combination of Napabucaisin with MG-132 exhibited a significant synergistic anti-proliferative effect, probably by inducing apoptosis through a mitochondria-dependent pathway. The two compounds induced pro-survival autophagies, and co-treatment with autophagy inhibiter might further enhance their antitumor effects.. Napabucasin alone or in combination with MG-132 might be promising treatment strategy for ovarian cancer patients.

Topics: Apoptosis; Benzofurans; Carcinoma, Ovarian Epithelial; Cell Cycle Checkpoints; Cell Line, Tumor; Cell Proliferation; Cell Survival; Cysteine Proteinase Inhibitors; Drug Synergism; Female; G2 Phase Cell Cycle Checkpoints; Humans; Leupeptins; Naphthoquinones; Ovarian Neoplasms; Proteasome Endopeptidase Complex; Proteasome Inhibitors; STAT3 Transcription Factor

Platinum-based combination chemotherapy after surgery is considered a standard treatment; therefore, any recent drug development should be new, effective, and low toxic, and should have a synergistic effect with platinum. This study aimed to observe the growth of SKOV3 cells after treatment with cisplatin by combining with carbobenzoxy-L-leucyl-L-leucyl-L-leucinal (MG132) and to investigate the effect of the relationship between MG132 and cisplatin combination.. Cell growth was detected by methyl thiazolyl tetrazolium assay after treatment with MG132 at 0.5, 1.5, 2.5, 3.5, and 5.0 μg/mL concentrations for 24, 48, and 72 hours; with cisplatin at 1.0, 2.0, 3.0, 4.0, and 5.0 μg/mL concentrations; and with combination with MG132 at 1.5 μg/mL for 24 hours. The apoptotic rates of cells were detected by a flow cytometer after cisplatin treatment at 1.0, 2.0, 3.0, and 4.0 μg/mL concentrations and that combined with MG132 at 1.5 μg/mL concentration for 12, 24, and 36 hours. A total of 20 BALB/c (nu/nu) female nude mice (age, 4-6 weeks; body weight, 17-19 g) were divided into 4 groups: control, MG132, cisplatin, and combination groups. The expression of Caspase3 and Beclin1 was detected by Western blot analysis and reverse transcription-polymerase chain reaction after treatment with 3.0 μg/mL of the cisplatin group and combined treatment with 1.5 μg/mL of MG132 group for 24 hours, respectively.. Methyl thiazolyl tetrazolium assay demonstrated the inhibitory rates, and the flow cytometery showed that the apoptotic rates in the combination group were higher than those in the cisplatin group (P < 0.01). Western blot analysis and reverse transcription-polymerase chain reaction detected that Caspase3 and Beclin1 at a relative quantity in the combination group were higher than those in the cisplatin group (P < 0.05).. MG132 has a synergistic antitumor effect by combining with cisplatin, and it is expected to be an effective antitumor drug for platinum-resistant refractory ovarian cancer.

Topics: Animals; Antineoplastic Combined Chemotherapy Protocols; Carcinoma, Ovarian Epithelial; Cell Growth Processes; Cell Line, Tumor; Cisplatin; Cysteine Proteinase Inhibitors; Drug Synergism; Female; Humans; Leupeptins; Mice, Inbred BALB C; Mice, Nude; Neoplasms, Glandular and Epithelial; Ovarian Neoplasms; Random Allocation; Xenograft Model Antitumor Assays